/*
 * Copyright (C) 2001-2011 Jacek Sieka, arnetheduck on gmail point com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef DCPLUSPLUS_DCPP_SEMAPHORE_H
#define DCPLUSPLUS_DCPP_SEMAPHORE_H

#ifdef _WIN32
#include "w.h"
#else
#include <errno.h>
#include <semaphore.h>
#include <sys/time.h>
#endif

#include "noexcept.h"

namespace dcpp {

class Semaphore
{
#ifdef _WIN32
public:
	Semaphore() noexcept {
		h = CreateSemaphore(NULL, 0, MAXLONG, NULL);
	}

	void signal() noexcept {
		ReleaseSemaphore(h, 1, NULL);
	}

	bool wait() noexcept { return WaitForSingleObject(h, INFINITE) == WAIT_OBJECT_0; }
	bool wait(uint32_t millis) noexcept { return WaitForSingleObject(h, millis) == WAIT_OBJECT_0; }

	~Semaphore() {
		CloseHandle(h);
	}

private:
	HANDLE h;
#else
public:
	Semaphore() noexcept { 
		sem_init(&semaphore, 0, 0); 
	}
	
	~Semaphore() {
		sem_destroy(&semaphore); 
	}

	void signal() noexcept { 
		sem_post(&semaphore); 
	}

	bool wait() noexcept {
		int retval = 0;
		do {
			retval = sem_wait(&semaphore);
		} while (retval != 0);

		return true;
	}

	bool wait(uint32_t millis) noexcept {
		timeval timev;
		timespec t;
		gettimeofday(&timev, NULL);
		millis+=timev.tv_usec/1000;
		t.tv_sec = timev.tv_sec + (millis/1000);
		t.tv_nsec = (millis%1000)*1000*1000;
		int ret;
		do {
			ret = sem_timedwait(&semaphore, &t);
		} while (ret != 0 && errno == EINTR);

		if (ret != 0) {
			return false;
		}

		return true;
	}

private:
	sem_t semaphore;
#endif
	Semaphore(const Semaphore&);
	Semaphore& operator=(const Semaphore&);

};

} // namespace dcpp

#endif // DCPLUSPLUS_DCPP_SEMAPHORE_H
